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Biomedical subjects

C Fischer

Publications and source records attributed to C Fischer.

At least 145 records · Page 8Linked to original sources
PubMed1997

Genetics of type III hyperlipoproteinemia.

One hundred forty-seven relatives of 43 patients with "classical" type III hyperlipoproteinemia (HLP) having the apolipoprotein (apo) E2/2 phenotype were studied to determine the occurrence of hyperlipidemia and the presence of further possible genes for lipoprotein disorders in these families. In 12 pedigrees primary dyslipidemia was prevalent among patients and respective blood-relatives. In these kindreds the coexistent presence of genes for familial combined hyperlipidemia (n = 6), familial hypertriglyceridemia (n = 5), and familial hypercholesterolemia (n = 1), respectively, was supposed. Our results, therefore, confirm and extend previous data on the multifactorial genesis of the diseases. Besides homozygosity for a receptor binding-defective isoform of apo E (apo E2), additional genes for familial lipoprotein disorders might operate in the pathogenesis of type III HLP. This is the largest family study performed so far in this primary lipoprotein disorder.

Adult↗
PubMed1997

Regulation of carbon metabolism in gram-positive bacteria by protein phosphorylation.

The main function of the bacterial phosphotransferase system is to transport and to phosphorylate mono- and disaccharides as well as sugar alcohols. However, the phosphotransferase system is also involved in regulation of carbon metabolism. In Gram-positive bacteria, it is implicated in carbon catabolite repression and regulation of expression of catabolic genes by controlling either catabolic enzyme activities, transcriptional activators or antiterminators. All these different regulations follow a protein phosphorylation mechanism.

Bacterial Proteins↗
PubMed1997

[Transurethral laser ablation of the prostate in high risk patients with obstructive benign prostatic hyperplasia. Perioperative morbidity and 6 month outcome in 72 patients].

Between November 1993 and September 1995, we carried out visual laser ablation of the prostate (VLAP) in 72 high-risk patients (ASA 3-4; severe cardiovascular and/or pulmonary diseases) aged 60-88 years (mean 76.7 years); the prostate volume was 22-136 ml (mean 56 ml). The urinary peak flow rates (Qmax.) ranged from 2 to 15 ml/s (mean 4.4 ml/s) preoperatively; 42 patients (58.3%) suffered from acute urinary retention for up to 2 weeks and had an indwelling catheter. The residual urinary volume (RUV) was 0-320 ml (mean 142.3 ml) in those 30 patients with spontaneous micturition. The International Prostate Symptom Score (IPSS) ranged from 10 to 33 (mean 21.8). In the first 37 patients, pressure-flow studies were carried out only in cases of doubt to verify obstruction. In the last 35 patients, pressure-flow studies were carried out in every case. Perioperatively, there was no appearance of blood loss of absorption of irrigation fluid. None of our patients needed transfusions or intensive care perioperatively. Further complications were not severe and could be handled without problems. In two patients with large benign prostate hypertrophy (BPH) a second operation (VLAP, no conventional transurethral prostatectomy) was necessary. After 6 weeks, 29.4% of the patients suffered from symptomatic urinary tract infections (UTI). After 6 months, only 7.1% of the patients had symptomatic UTI. After 6 weeks (n = 61), Qmax. was 6-34 ml/s (mean 15.3 ml/s), RUV was 0-230 ml (mean 51.5 ml), and the IPSS was 12.3 (8-28). After 3 months (n = 54), Qmax. was 9-45 ml/s (mean 19.8 ml/s), RUV was 0-96 ml (mean 31.6 ml), and the IPSS was 1-23 (mean 7.4). After 6 months (n = 52) Qmax. was 12-33 ml/s (mean 20.4 ml), RUV was 0-53 ml (mean 26.4 ml), and the IPSS was 1-12 (mean 4.1). VLAP provided no further risks for our high-risk patients, while Qmax., RUV, and IPSS were improved noticeably (improvement of more than 75%). It represents a step forward in the treatment of obstructive BPH in high-risk patients. Particularly in high-risk patients with cardiac diseases, this procedure lessens the perioperative risk. Despite the minimal appearance of UTI after 6 months, UTI seemed to be the most important complication during the first few weeks after VLAP by virtue of the bothersome symptoms.

Aged↗
PubMed1997

High-resolution comparative hybridization to combed DNA fibers.

Comparative genomic hybridization (CGH) has proven to be a comprehensive new tool to detect genetic imbalances in genomic DNA. However, the resolution of this method carried out on normal human metaphase spreads is limited to low copy number gains and losses of > or = 10 Mb. An improved resolution allowing the detection of copy number representations of single genes would strongly enhance the applicability of CGH as a diagnostic and research tool. This goal may be achieved when metaphase chromosomes are replaced by an array of target DNAs representing the genes of interest. To explore the feasibility of such a development in a model system we used cosmid MA2B3, which encompasses about 35 kb in the vicinity of exon 48 of the human dystrophin gene. Linearized cosmid fibers were attached to a glass surface and aligned in parallel by "molecular combing". Two-color fluorescence in situ suppression hybridization was performed on these cosmid fibers with probe mixtures containing different ratios (ranging from 1:2 to 4:1) of biotin- and digoxigenin-labeled MA2B3 cosmid DNAs. For each mixture fluorescence ratios were determined for 40-50 individual combed DNA molecules. In two series comprising a total of 651 molecules the median fluorescence ratio measurements revealed a linear relationship with the chosen probe ratios. Our study demonstrates that fluorescence ratio measurements on single DNA molecules can be performed successfully.

Biotin↗
PubMed1997

Another pedigree with pure autosomal dominant spastic paraplegia (AD-FSP) from Tibet mapping to 14q11.2-q24.3.

The mutant in a family with autosomal-dominant spastic paresis in Northern Tibet was mapped by linkage analysis with several microsatellite markers to a gene locus at 14q11.2-q24.3, an area to which a few mutants leading to a condition with similar clinical signs have previously been mapped. The mutant observed in this pedigree probably arose de novo. Gene loci at 2p21-p24 and 15q, which have been found for other pedigrees with dominant spastic paresis, were excluded. The data in this pedigree do not contradict the hypothesis proposed by another group that there might be anticipation.

Adult↗
PubMed1997

Dynamics of MLAEP changes in midazolam-induced sedation.

This study aimed at assessing the effects of midazolam (MDZ) sedation on auditory brainstem (BAEP) and middle latency (MLAEP) evoked potentials in intensive care conditions. Ten ventilated comatose patients were receiving an intravenous MDZ bolus dose (0.2 mg/kg) followed by a 2 h continuous infusion (0.1 mg/kg/h). MLAEPs and BAEPs elicited by clicks (90 dB HL + masking) were simultaneously and continuously monitored during the first 6 h and for 30 min the next morning. We found no effect of MDZ sedation on BAEPs. Only MLAEP components were modified. However, none of the patients presented any total abolition of the MLAEPs. Bolus injection led to very early alteration of cortical responses, beginning after 5 min and lasting almost 1 h (maximum Pa latency increase, 3.1 ms; maximum Pa-Nb amplitude decrease, 46%). During continuous infusion, MLAEPs remained slightly, although significantly, altered (Pa latency, +1.3 ms; Pa-Nb amplitude, 27%). The Nb wave seemed to be modified earlier and to return to normality later than the Pa wave. These findings incite a careful interpretation of MLAEP tracings acquired during the first hour following MDZ bolus injection. If possible, MDZ should be administered as continuous infusion for reliable interpretation of evoked potential changes in intensive care unit, or during surgery.

Adult↗
PubMed1997

[The use of EEG in the diagnosis of brain death in France].

Scientific and modern conception of brain-death is rather recent, thus making possible organ transplantations. During the past three decades clinical criteria for brain-death have been defined. Electroencephalography (EEG) appears to be a complementary tool as it permits brain-death assessment. In France laws enforced respectively in 1968, 1978, 1991 and 1996 provide a framework for brain-death evaluation before organ transplantation and include EEG recording. Advantages and pitfalls of EEG in the diagnosis of brain-death are considered as this technique may be unreliable. Only evoked potential recordings can allow assessment and confirmation of brain stem death, which is a mandatory criterion. We recommend simultaneous EEG and either brain stem auditory or somatosensory evoked potential recordings to strengthen clinical criteria of brain-death and definitely prove it using objective electrophysiological criteria.

Brain Death↗
PubMed1997

Cerebrospinal fluid neuropeptides and monoaminergic transmitters in patients with trigeminal neuralgia.

The pathogenesis of trigeminal neuralgia remains largely unknown. "Peripheral" as well as "central" causes have been suggested. To investigate the role of serotonergic, noradrenergic, dopaminergic, and peptidergic systems, we determined the concentrations of epinephrine, norepinephrine, and their breakdown product, vanillylmandelic acid, in the cerebrospinal fluid of 16 patients (55.3 +/- 8.3 years) with trigeminal neuralgia. As a marker for the dopaminergic system, we determined cerebrospinal fluid concentrations of dopamine and its metabolite, homovanillic acid. As a marker for the serotonergic system, we measured cerebrospinal fluid levels of the serotonin metabolite, 5-hydroxyindoleacetic acid. In addition, levels of the neuropeptides, substance P and somatostatin, were determined. The concentration of norepinephrine (P < 0.01) and its metabolite, vanillylmandelic acid, (P < 0.05) were significantly decreased in our patients. The level of the dopamine metabolite, homovanillic acid, was also significantly reduced (P < 0.01). Also significantly decreased was 5-hydroxyindoleacetic acid (P < 0.01). Substance P was significantly elevated (P < 0.05). Somatostatin was significantly decreased (P < 0.05). We hypothesize that the sum of complex neurochemical changes plays a role in the pathogenesis of trigeminal neuralgia. The elevated substance P could support the concept of a neurogenic inflammation in the trigeminovascular system, whereas changes in the monoaminergic transmitters and their metabolites seem to reflect a more central dysfunction possibly due to a longer duration of the disease and an accompanying depression.

Biogenic Monoamines↗
PubMed1997

Treatment of Graves' hyperthyroidism with radioiodine: results of a prospective randomized study.

In this paper, we report the results of a randomized prospective study on radioiodine treatment in patients with Graves' hyperthyroidism. Complete data were obtained in group 1 from 98 patients 6 months after application of a standard activity of 15 mCi (555 MBq) of 131I and in group 2 from 107 patients who received a target dose of 100 Gy. In group 1, the overall success rate was 71%, but the results in the subgroups clearly were related inversely to the thyroid volume, ranging from 100% in patients with a thyroid volume < 15 mL to about 20% in those with a thyroid size of > 60 mL. In contrast, patients who received a target of 100 Gy showed very similar results, with success rates of about 40-50% in all but one subgroup. Only patients with a thyroid volume < 15 mL had a success rate of about 80%. But due to an incidental increase of uptake and/or effective half-time from the test to the therapy activity, this subgroup received a target dose of about 160 Gy. Additional calculation of the actual target dose in group 1 (standard activity) showed that, with a dose of 200 Gy, a success rate of 80% was obtained. Also, the thyroid volume reduction was related inversely to the target dose. Because the literature is abundant, only a restricted number of references are discussed that are either in agreement with our results or in sharp contrast to them. The reason for these discrepant results might be the difference in the scheme of pretreatment or the different alimentary iodine supply between, for example, Great Britain and the United States on the one hand and Germany on the the other hand.

Adult↗
PubMed1997

Predictions of carbamazepine concentrations using a Bayesian program (PKS System, Abbott): a retrospective evaluation in an outpatient population.

This work evaluates the performance of a Bayesian program (PKS System, Abbott) for predicting carbamazepine concentrations in an outpatient population. The retrospective study involved 20 epileptic patients (12 adults and 8 children) receiving carbamazepine monotherapy orally. The program was used to predict measured serum levels after feedback of 0, 1 or 2 steady-state concentrations. A significant negative prediction bias was observed when no feedback concentration was used for estimation. However, the prediction bias (mean prediction error; m.e.) decreased as soon as one feedback concentration was used for estimation. Precision (mean absolute prediction error; m.a.e.) was significantly improved with one feedback concentration and was even better with two concentrations. Likewise, r.m.s.e. (root mean squared error; composite of bias and precision) regularly decreased when the number of feedback concentrations used was increased. Eleven percent of the estimates were unacceptable clinically (prediction error > 2 mg L-1) when 1 feedback concentration was used; less than 3% were unacceptable when two concentrations were used. Thus the performance of the Bayesian dosing program is acceptable when two feedback concentrations are known, and seems able to help the clinician adjust carbamazepine dosage in an outpatient population.

Administration, Oral↗
PubMed1997

Microvascular decompression for the treatment of hemifacial spasm. Retrospective study of a consecutive series of 75 operated patients--electrophysiologic and anatomical surgical analysis.

The authors report the results of a series of 75 patients operated on for hemifacial spasm by the same surgeon between October 1981 and January 1997. Microsurgical vascular decompression was performed through a retromastoid approach in contralateral position. The conflicting vessel was identified as the posterior inferior cerebellar artery in 41.3% of the cases, the anterior inferior artery in 38.6%, and the vertebrobasilar complex in 18.7%. Follow-up varied from 1 month to 13 years (with a mean duration of 5 years and 2 months). The outcome was excellent (total improvement) in 57 cases, good (> 75% improvement) in 11 cases, fair (< 75%) in 4 cases and poor in 3 cases. Neurological complications included deafness or hearing loss in 3 cases (2 occurred in the absence of intraoperative monitoring and the other during the first part of the series) and facial paralysis in 1 case. Brainstem auditory evoked potential (BAEP) intraoperative monitoring should be performed to avoid postoperative auditory complications; a marked auditory loss was observed in only 1.6% of the 60 patients of our series who underwent BAEP intraoperative monitoring.

Adult↗
PubMed1997

Small-bowel diverticulosis: perceptions and reality.

BACKGROUND: Small-bowel diverticulosis is a rare entity that can be discovered incidentally during celiotomy, endoscopy, or radiographic imaging studies. The reported complication rate is low, giving rise to the current recommendation not to treat uncomplicated small-bowel diverticula. STUDY DESIGN: A retrospective review was performed of patients with small-bowel diverticulosis seen during 23 years at three major institutions. RESULTS: Two hundred eight patients were identified. Diverticula were located in the duodenum in 79 percent; in the jejunum or ileum in 18 percent; and in duodenum, jejunum, and ileum in 3 percent. Complications developed in 42 of the 208 patients (20 percent) including bleeding in 14, diverticulitis with perforation and abscess formation in 12, and malabsorption in 8. When assessed by location, jejunoileal diverticula were more likely to have complications than duodenal diverticula: 46 percent compared to 13 percent (p < .01). Bleeding accounted for 52 percent of the duodenal complications compared to 12 percent of the jejunoileal complications (p < 05). Jejunoileal diverticula were more likely to perforate and develop abscesses (21 percent compared to 1.2 percent; p < .001). CONCLUSIONS: The low incidence of complications associated with duodenal diverticula justifies a nonoperative approach. The higher complication rate associated with jejunoileal diverticula will be necessary to define that approach more exactly.

Adult↗
PubMed1997

[Faulty regulation of the hypothalamo-hypophyseal-adrenal axis and chronobiological manifestations in cluster headache].

Cluster headache is a rare very severe disorder that is clinically well characterized with a relatively poorly understood pathophysiology. Although peripheral structures are postulated to be involved in triggering the pain attacks, chronobiological changes like the cluster period and the complex dysbalance of the sympathetic and parasympathetic nervous system point to a "central" genesis of cluster headache. To check neuroendocrine changes in cluster headache, in 12 patients (43.4 +/- 6.3 years) during the cluster period cortisol and ACTH were determined four-times a day (7.00, 12.00, 17.00, 23.00) in the plasma. To prove the central genesis of cluster headache, in the cerebrospinal fluid (CSF) the neurotransmitters norepinephrine, epinephrine, dopamine and the metabolites 5-hydroxyindolacetic acid (5-HIAA), homovanillic acid (HVA) and vanillymandelic acid (VMA) were determined. The values of cortisol and ACTH were significantly elevated in the morning (p < 0.01, p < 0.05) and at night (p < 0.01, p < 0.01) in comparison to the control patients. The daily mean value of cortisol was significantly increased compared to controls (p < 0.01). In the CSF norepinephrine (p < 0.05), HVA (p < 0.01) and 5-HIAA (p < 0.01) decreased to significant low levels compared to control patients. We found significant correlations between cortisol/ACTH and norepinephrine and 5-HIAA. Moreover, our results indicate that the higher cortisol the longer the duration of the cluster period. The results of this study confirm changes of the hypothalamic-pituitary-adrenal axis due to the chronobiological changes in cluster headache. The reduced values of neurotransmitters in the CSF are compatible with the hypothesis of a central genesis of cluster headache.

Adrenocorticotropic Hormone↗
PubMed1997

Effects of altitude hypoxia on middle latency auditory evoked potentials in humans.

BACKGROUND: This paper presents an investigation of auditory evoked responses in humans subjected to high altitude hypoxic conditions. METHODS: Middle latency (MLAEPs) as well as short latency (BAEPs) evoked potentials were recorded in 10 healthy subjects, first at sea level (N), then 24 h (H1) and 72 h (H3) after their arrival at an altitude of 4350 m. At the same time, arterial blood parameters (PaO2, PaCO2 and pH) were measured and the clinical status of the subjects was assessed. RESULTS: In altitude conditions, the amplitude of BAEP peak V decreased (-17%). The MLAEP waves showed variations in the shape of their latest waveforms. Their amplitudes, however, were not affected. The Pa-Nb interpeak latency significantly decreased (-2.2 ms) between N and H1, and remained stable during the stay at high altitude. CONCLUSION: A correlation was found between the relative decrease of PaCO2 and the shortening of Nb wave latency, suggesting that the variations in MLAEPs could be preferentially related to the ventilatory response of the subjects in hypoxic conditions. However, no correlation was found between the clinical status of the subjects (Acute Mountain Sickness score) and the parameters of the waves.

Adaptation, Physiological↗
PubMed1996

[Substance P, somatostatin and monoaminergic transmitters in the cerebrospinal fluid of patients with chronic idiopathic trigeminal neuralgia].

The etiology of trigeminal neuralgia is unknown, but both peripheral and central causes have been suggested. To investigate the role of central neurochemical mechanisms we measured epinephrine, norepinephrine and their breakdown product, vanilly mandelic acid (VMA), in the cerebrospinal fluid (CSF) of 16 patients (53.3 +/- 8.3 years) suffering from trigeminal neuralgia. As markers for the dopaminergic system, we determined CSF levels of dopamine and its metabolite homovanillic acid (HVA). As a marker for the serotonergic system, we measured CSF levels of serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA). In addition, levels of the neuropeptides substance P and somatostatin were determined. The concentration of norepinephrine (P < 0.01), VMA (P < 0.05) and HVA (P < 0.05) were significantly decreased in patients with trigeminal neuralgia and correlated with the duration of the disease and depression scores. 5-HIAA was also significantly decreased (P < 0.05) compared to control patients. Whereas substance P was significantly elevated (P < 0.05), somatostatin was significantly decreased (P < 0.05). Various correlations between the classical neurotransmitters and the neuropeptides could be established. We hypothesize than the sum of complex neurochemical changes plays a role in the etiology of trigeminal neuralgia, which can be separated in local and more central proceedings. The increase in substance P, a major nociceptive neuromodulator, supports the concept of a local neurogenic inflammation, possibly located in the trigeminovascular system. Depending on the duration of the disease and depression, the loss of serotonergic, dopaminergic and noradrenergic innervation seems to reflect more central changes, possibly due to alterations in their antinociceptive descending pathways.

English Abstract↗
PubMed1996

[Reduced sympathetic nervous system activity during the cluster period of cluster-headache].

Cluster headache is a rare, very severe disorder that is clinically well characterized with a relatively poorly understood pathophysiology. Alterations of the hypothalamic-pituitary axis due to chronobiological changes, such as typical temporal pattern of both cluster periods and attacks, point to a central etiopathogenesis. Multiple local and systemic autonomic symptoms are compatible with an altered balance of the sympathetic and parasympathetic nervous system. In this connection, too, a central etiology is postulated. To evaluate the activation of the sympathetic nervous system, in 12 cluster headache patients we investigated the plasma catecholamines norepinephrine and epinephrine four times a day (7.00, 12.00, 17.00, 23.00) in the cluster period. In the cerebrospinal fluid we determined the transmitters norepinephrine, epinephrine, dopamine and the metabolites homovanillic acid (HVA), vanillymandelic acid (VMA) and 5-hydroxyindoleacetic acid (5-HIAA). Values of plasma norepinephrine in the morning (p < 0.01), in the evening (p < 0.01) and the daily mean value (223.8 = 58.3 nmol/ml) were significantly decreased in the cluster headache group in comparison to the control group (328.8 = 53.0 nmol/ml, p < 0.01). The plasma epinephrine showed no significant changes. In the CSF of cluster headache patients norepinephrine (p < 0.05), HVA (p < 0.01), and 5-HIAA (p < 0.01) were significantly decreased. Plasma norepinephrine was correlated with CSF values of HVA and 5-HIAA. The longer the duration of the disease, the lower the values of HVA and 5-HIAA in the CSF of cluster headache patients. Moreover, plasma norepinephrine showed a significant correlation with the duration, the intensity and the frequency of the attacks. The results of this study implicate decreased activity of the sympathetic nervous system with alteration of circadian rhythmicity during the cluster period. The decreased CSF transmitter values may support the hypothesis of a central etiopathogenesis of cluster headache. Moreover, plasma norepinephrine seems to be involved in triggering and continuing the attacks. The anatomical region in which this interface of sympathetic and neurogenic inflammatory processes might be located is the trigemino-vascular system.

Adult↗
PubMed1996

Altered activity of the sympathetic nervous system and changes in the balance of hypophyseal, pituitary and adrenal hormones in patients with cluster headache.

Twelve patients (age 43.4 +/- 6.3 years) with episodic cluster headache (CH) were examined during the cluster period. Plasma norepinephrine levels in patients suffering from CH were significantly decreased compared with the control group (p < 0.01). There were also statistically significant correlations between norepinephrine levels and clinical features of the pain attacks including duration (r = 0.75, p < 0.05), intensity (r = 0.64, p < 0.05) and frequency (r = 0.68, p < 0.06), thereby suggesting a pathophysiological involvement of the sympathetic nervous system in CH. Increased plasma levels of plasmacortisol and ACTH in patients with CH, especially in the morning and in the evening, suggest an alteration of the feedback circuit involving the hypothalamus, the pituitary and the adrenal gland, an imbalance in the hormones related to these structures, as well as an alteration of the circadian rhythm. In addition, CH patients demonstrated significantly decreased levels of norepinephrine (p < 0.05), HVA (p < 0.01) and 5-HIAA (p < 0.01) in the cerebrospinal fluid (CSF) consistent with a central genesis of CH. These significant relationships between neurochemical parameters and the clinical patterns suggest a complex interplay between the hypothalamus, neuroendocrinological parameters, activity of the autonomic nervous system and the pain of CH.

Adrenal Cortex Hormones↗